JP2002273805A - Fiber-reinforced resin coated steel pipe and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-strength polyolefin heavy-duty corrosion resistant coated steel pipe having a coating excellent in impact resistance against an impact caused by ripraps, suspended matters including ships or the like at the time of burying the steel pipe needing a corrosion resistant coating on its outer surface, at the time of driving a steel pipe pile or after the steel pipe pile is driven. SOLUTION: The heavy-duty corrosion resistant coated steel pipe comprises the corrosion resistant coating executed on its outer surface. A method for manufacturing the heavy-duty corrosion resistant coated steel pipe comprises the steps of rotating the steel pipe having the corrosion resistant coating executed on the outer surface, and winding a glass roving on the surface of the steel pipe to cover 20 to 80% of one time coating area in an area ratio by holding a uniform interval on a part in which a cut matter having 5 to 100 mm of a glass roving and an unsaturated polyester resin containing a peroxide catalyst and a reactive monomer are spray painted onto the surface of the steel pipe. Thus, an FRP protective layer is formed on the surface of the steel pipe. Accordingly, the FRP-coated steel pipe and the steel pipe pile can be easily manufactured and have higher impact resistance as compared with conventional products.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for burying steel pipes requiring an anticorrosion coating on the outer surface, or for placing steel pipe piles at a steel structure such as a pier or seawall in a port or river, or after placing. The present invention relates to a steel pipe pile with heavy corrosion protection on the outer surface, which is excellent in impact resistance and durability of a corrosion protection coating against impacts generated by discarded stones and other floating matters including ships, and a method of manufacturing the same.

[0002]

2. Description of the Related Art When steel pipes and steel pipe piles requiring external corrosion protection are required to have long-term durability for several decades, heavy corrosion protection coated steel materials using a polyolefin or polyurethane resin as a coating material are manufactured. . Heavy corrosion protection coated steel using such a coating material is remarkably excellent in corrosion resistance,
The strength of the resin used is low, and the occurrence of coating flaws due to collision or friction in handling during transportation, storage, and construction has become a problem. On the other hand, Japanese Patent Laid-Open No. Hei 10-24272
9 and a method for improving the scratch resistance by simultaneously coating a glass fiber and a polyester or urethane elastomer on a corrosion-resistant coating made of a polyolefin or a polyurethane resin as proposed in JP-A-10-272728. Has been proposed.

[0003]

When a fiber reinforced resin (referred to as FRP) having excellent strength and hardness is formed on the surface layer of a heavy-duty anticorrosion coating, FRP is less expensive than lightweight but expensive fibers such as carbon fiber and aramid. And high strength glass fiber is mainly used. When glass cloth is used as the type of glass fiber to be used, the strength becomes an excellent manufacturing method. However, since it is expensive and there is a possibility of causing directionality and interlayer cracking due to the manufacturing method, using a glass chop (short fiber) is inexpensive. A uniform FRP layer can be coated. For example, in JP-A-10-242729, winding coating using a glass mat is performed. Also, Japanese Patent Application Laid-Open No. 10-272728
Then, the FRP layer is formed by simultaneously spraying and applying a chop obtained by cutting the glass roving by a spray-up method and a polyester resin paint. JP-A-10-2427
Although winding coating using a glass mat as in No. 29 has a problem in productivity, the method of forming an FRP layer by spraying up as in Japanese Patent Application Laid-Open No. Hei 10-272728 is easy to adjust the coating length, thus improving productivity and performance. Excellent.

[0004] However, spray-up coating requires time for defoaming work after coating because air bubbles are involved in the FRP coating at the time of coating. Also, if the thickness of the FRP protective coating is 3 mm or more due to the requirement of impact resistance, the coating film may fall off during painting or when it is allowed to stand still after painting, especially for steel pipes with relatively small diameters such as 200 to 600A. There was a problem that occurs. On the other hand, in a method of manufacturing an FRP tube, while immersing a large number of glass rovings in a resin,
Filament winding around the tube (F
W). FW is an excellent method for producing a large number of FRP tubes of the same size, but has a low degree of freedom in coating and is not suitable for coating with a short coating length. In addition, the rotation speed of the pipe is also a problem when coating heavy objects.

Accordingly, the present invention proposes, as a method of forming an FRP layer on an anticorrosion coating, a coating method in which the defoaming property of a coating film, which is a problem of the conventional spray-up method, and the resistance to falling off are improved. Developed a high-strength heavy-duty corrosion-resistant coated steel pipe with excellent impact resistance.

[0006]

Means for Solving the Problems As means for solving the above-mentioned problems, the present inventors rotated a steel pipe coated with heavy corrosion protection using polyolefin or polyurethane as shown in FIG. 5 to 100 mm cut pieces of glass roving, and an unsaturated polyester resin to which a peroxide catalyst and a reactive monomer were added were sprayed on the surface of the roving, and evenly spaced portions were maintained at a uniform interval of 10 to 10 By winding a glass roving so as to have an area ratio of about 80% to form an FRP protective layer on the surface, it is possible to perform coating excellent in defoaming property and falling resistance.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the present invention, a heavy corrosion-resistant coated steel pipe or a steel pipe pile is used. Heavy corrosion protection coated steel pipe or steel pipe pile is a blast treatment,
It is manufactured by laminating a heavy corrosion protection coating layer having a thickness exceeding 0.5 mm on a steel pipe which has been subjected to a base treatment such as a chromate treatment. When a polyolefin is used for the heavy-duty anticorrosion coating, the polyolefin has no polar group in the molecular skeleton and thus has poor adhesion, so the polyolefin coating is laminated via a modified adhesive. Similarly, since FRP coated on the upper layer also has poor adhesion, irregularities on the surface of the polyolefin, or physical methods such as spiral projections, or introduction of a polar group by flame treatment, discharge treatment or the like may be performed. .
On the other hand, when polyurethane is used, no particular treatment is required, but a primer treatment may be performed to improve the adhesive strength.

Next, an FRP protective layer, which is a cured product of glass fiber and an unsaturated polyester resin, is formed on the outer surface of the heavy corrosion-resistant coated steel pipe. The outline is shown in FIG. The steel tube 1 coated with heavy corrosion protection is spirally rotated, and the glass roving 4 is sprayed with the rotary cutter of the spray-up gun 2 for 5 to 10 minutes.
It is cut and supplied with a length of 0 mm, and the peroxide-unsaturated polyester resin is supplied from the coating pump 3 and sprayed at the tip of the gun 2 simultaneously with the glass fiber chop. A plurality of glass rovings 6 are wound around the surface so as to maintain an even interval and to have an area ratio of 10 to 80% with respect to one coating area. If the area ratio of the glass roving is 10% or less, falling off occurs, and if it is 80% or more, the roving hinders and a problem arises in the defoaming property. Therefore, the number of glass rovings is 10 to 80%. To adjust. Also,
By defoaming the coating film by the defoaming roll 7 at the same time as the coating, the bubble rate in the FRP can be reduced. By combining the glass fiber chop and the winding coating of the glass roving in this manner, it is possible to reduce the defoaming work and to form an FRP coating that does not drop off until the polyester coating is cured.

The unsaturated polyester cured resin used for coating may be any resin having an ester bond and a double bond in the molecule, and may be an orthophthalic acid type, isophthalic acid type, terephthalic acid type or bisphenol type unsaturated polyester resin. Can be used. Although there is a problem of material cost, a vinyl ester which is chemically stable and has a terminal double bond may be used. A solution of these unsaturated polyester resins in which a polymerizable monomer such as a styrene monomer is dissolved at a content of 30 to 60% is prepared by mixing a peroxide catalyst such as ketone peroxide and hydroperoxide with a cobalt-based or vanadium-based catalyst. A thermosetting resin that is cured by an accelerator such as a manganese, an amine or the like is used. On the other hand, as the added fiber, glass fiber is used because it is excellent in price, resin reinforcing effect, and anticorrosion performance. As the glass fiber, a commercially available glass roving is used, and the amount of glass is adjusted so as to be 10% by weight or more. If the length of glass fiber is short, strength improvement effect cannot be obtained.
Add above. In the spray-up method, if the length of the glass fiber is long, the defoaming property of the paint is reduced.

The polyester resin layer is colored by adding a coloring pigment for imparting design and weather resistance. Examples of the coloring pigment used include, for example, cadmium yellow, iron oxide, polyazo yellow, quinophthalone yellow, isoindolinone yellow, quinacridone yellow, bengara red, polyazo brown, azo lake yellow, perylene red, phthalocyanine blue, phthalocyanine green, and bengala. 0.2 to 3% of yellow, cobalt aluminate, aniline black, carbon black, titanium oxide, ultramarine blue, aluminum fine powder, etc.
Added. In particular, when weather resistance is required, a colored unsaturated polyester cured resin layer containing no glass fiber may be further formed on the outermost surface. For this reason, after forming the glass fiber reinforced polyester protective coating layer, the surface thereof is coated with an unsaturated polyester resin containing a coloring pigment in an amount of 200 to 1500 μm.
Paint with a thickness of m. To give the unsaturated polyester cured resin layer of the composition the function and adhesion as a protective layer,
A film of 2 to 10 mm is formed. If the thickness is less than 2 mm, the impact resistance and the shear adhesion are reduced. If the thickness exceeds 10 mm, the amount of heat generated during curing increases.

FIG. 2 shows an example of a cross-sectional view of a coating produced by the production method of the present invention. In the cross-sectional configuration of the coating, the anticorrosion function is maintained by the heavy anticorrosion coating layer 10. Also, FR
High impact resistance is obtained by combination with the P layer 5. Since the glass roving 6 wound at the same time as the FRP layer 5 is a long fiber of at least one circumference of the steel pipe, it has an effect of preventing the FRP layer 5 from falling off before being hardened. In addition, the defoaming property can be maintained by not making the glass roving interval dense.

[0012]

[Example] Outer diameter 200A x length 5500mm x wall thickness 5.8
After performing a grid blasting process on the outer surface of the steel pipe having a thickness of 0.5 mm to remove scale and the like and impart a roughness to the surface, a chromium-silica-based chromating agent is applied at a total chromium deposition amount of 500 mg / m ^2.
After applying and drying, a base treatment was performed. next,
A primer using an amine-based curing agent and a main component of a bisphenol A type epoxy resin was spray-coated so as to have a film thickness of 30 to 60 μm, and the steel material was heated to cure the primer. Then, a polyethylene adhesive modified with maleic anhydride (film thickness: 150 μm) and the polyethylene resin for anticorrosion coating of the present invention were extruded and coated in a film shape with a two-layer T-die. Thereafter, the mixture was cooled to produce a polyethylene corrosion-resistant steel pipe having a thickness of 2.5 mm and a density of 0.92 g / cm ³ .

Next, the glass roving was applied to the gun while spray-mixing a paint obtained by adding a 1% colored toner to an unsaturated polyester resin and a peroxide catalyst-containing curing agent by a spray-up method according to the layout shown in FIG. 25 at the tip
The cut pieces having a length of mm were simultaneously spray-coated at a ratio of 30% by weight to apply a colored protective layer. Then 7
A glass roving having a width of mm was wound around a steel pipe at an interval of 0 to 50 mm. At the same time, defoaming was performed by pressing a defoaming roll against the rotating steel pipe. This operation was repeated four times, and FIG.
An FRP-coated steel pipe having the cross-sectional structure shown in FIG. The coated FRP film thickness was 4 mm. Immediately after the coating, the rotation of the steel pipe was stopped in a state where the polyester resin had not been cured, and the steel pipe was left to be cured, but the coating film did not fall off.

On the other hand, for comparison, spray-up coating was attempted by omitting the glass roving for holding the coating film and the defoaming roll from the above-mentioned method of the present invention, but dropping occurred after three times of repeated coating. . In addition, when the coating was performed by combining only the defoaming roll with the spray-up, it was possible to prevent the falling off up to the fourth coating. However, when the rotation of the steel pipe was stopped after the coating, the falling off occurred similarly. Also, Japanese Patent Application Laid-Open No. 10-24
As a comparative example corresponding to 272, a base treatment was performed 200
In the case where the outer surface of the steel pipe of A is coated with polyethylene, a polyethylene extruded film from a part of the T-die is cut and separated and spirally coated to form a polyethylene-coated steel pipe having a surface step formed thereon.
The FRP protective layer was formed by the spray-up method described in 2, but it fell off during the third coating. For this reason, the method was carried out for each coating, and the steel pipe was left rotating until the hardening of the coating was completed. As is clear from the above results, the conventional FRP coating on the outer surface of the steel pipe by spray-up is performed until the coating is completely hardened because the coating falls off if the rotation of the steel pipe is stopped during coating or before the coating is hardened. The steel pipe had to be left rotating, and productivity was a problem.

The FRP-coated steel pipe produced by the above method was cut, and the penetration energy of the coating was measured by a falling weight impact test specified in ASTM G14. Table 1 shows the results. As is clear from the results in Table 1, the use of the coating method of the present invention can prevent the steel pipe from falling off after coating or after coating until the coating is cured. The use of a glass roving wound in a spiral shape is more effective for impact resistance. However, if the number of glass rovings is excessively increased, defoaming of the lower layer coating film is hindered, so that impact resistance decreases. Therefore, a suitable interval (10 to 80 in area ratio) is set as the range of the present invention.
%) Must be maintained.

[0016]

[Table 1]

[0017]

As is clear from the examples, the method for producing the FRP-coated steel pipe of the present invention has a significantly improved workability as compared with the conventional hand lay-up, and a coating film which is easily formed by spray-up. We established a coating method that prevents falling off and improves the strength of the coating. Thereby, the productivity and quality are improved, and the FRP coated steel pipe can be provided more easily.

[Brief description of the drawings]

FIG. 1 is a view showing a method for manufacturing an FRP-coated steel pipe of the present invention.

FIG. 2 is an axial sectional view of an FRP-coated steel pipe manufactured by the manufacturing method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heavy corrosion protection coated steel pipe 2 Spray-up gun 3 Resin pump 4 Glass roving 5 Glass fiber chop and resin coating 6 Glass roving 7 Defoaming roll 8 Steel pipe 9 Base treatment layer 10 Heavy corrosion protection coating layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B32B 15/08 103 F16L 9/16 105 C23F 11/00 G F16L 9/02 B29K 67:00 9/16 105 : 08 // C23F 11/00 105: 20 B29K 67:00 B29L 23:00 105: 08 B29C 67/14 A 105: 20 E B29L 23:00 67/18 F term (reference) 3H111 AA01 BA02 BA15 BA25 BA26 BA34 CA03 CA52 CB04 CB08 CB10 CB14 CB23 CC03 CC04 CC07 DA08 DA12 DB15 DB17 EA05 EA15 4F100 AA20 AA22 AB03A AG00C AG00D AG00E AK03B AK04G AK44C AK44E AK51B AK53 AK62B AK66B AL07G BA04 BA05 BA07 BA10A BA10D CB00 DA11 DA11A DE05C DE05E DG01C DG01D DG01E DH02C DH02E EH23 EH462 EH512 EH61C EH61E EH612 EJ67 EJ69 GB90 JB02 JB02B JK10 JL02 YY00C YY00E 4F205 AA03 AA31 AA41 AD03 AD05 AD16 AD20 AG03 AG08 HK02 HK05 HK16 HK22 HL03 HL12 H L14 HM05 HT02 HT03 HT06 HT08 HT22 HT24 4K062 AA01 BA14 BA20 BC07 BC13 BC15 CA10 FA04

Claims (4)

[Claims] 1. A steel pipe coated with a polyolefin or polyurethane on its outer surface and coated with a heavy-duty anticorrosion coating is spray-coated with a cut product obtained by cutting a glass roving together with an unsaturated polyester resin. A fiber-reinforced resin-coated steel pipe characterized by forming a fiber-reinforced resin-coated layer formed by winding the above. 2. The fiber-reinforced resin-coated steel pipe according to claim 1, wherein a plurality of fiber-reinforced resin coating layers are formed. 3. A cut piece obtained by cutting a glass roving into 5 to 100 mm together with an unsaturated polyester resin is spray-coated on the surface of a steel pipe coated with a heavy-duty anti-corrosion coated with polyolefin or polyurethane on the outer surface, and spray-coated. A fiber reinforced resin coating layer formed by winding a glass roving so as to have an area ratio of 10 to 80% with respect to one coating area while maintaining a uniform interval. Resin coated steel pipe. 4. An anticorrosion-coated steel pipe having an outer surface coated with polyolefin or polyurethane is rotated, and a cut piece of 5 to 100 mm of glass roving is cut on the surface, and an unsaturated polyester resin obtained by adding a peroxide catalyst and a reactive monomer. Spray painting is performed together, and a series of rotating operations such as winding a glass roving so as to have an area ratio of 10 to 80% with respect to the painting area are performed a plurality of times, while maintaining an even interval on the painting, A method for producing a fiber-reinforced resin-coated steel pipe, comprising forming a fiber-reinforced resin-coated protective layer.